# List of United States senators from Iowa

Iowa was admitted to the Union on December 28, 1846, and elects United States senators to class 2 and class 3. The state's current U.S. senators are Republicans Chuck Grassley (serving since 1981) and Joni Ernst (serving since 2015). Chuck Grassley is Iowa's longest-serving senator (since 1981).

## List of senators

| Class 2Class 2 U.S. senators belong to the electoral cycle that has recently been contested in 2002, 2008, 2014, and 2020. The next election will be in 2026. | Class 2Class 2 U.S. senators belong to the electoral cycle that has recently been contested in 2002, 2008, 2014, and 2020. The next election will be in 2026. | Class 2Class 2 U.S. senators belong to the electoral cycle that has recently been contested in 2002, 2008, 2014, and 2020. The next election will be in 2026. | Class 2Class 2 U.S. senators belong to the electoral cycle that has recently been contested in 2002, 2008, 2014, and 2020. The next election will be in 2026. | Class 2Class 2 U.S. senators belong to the electoral cycle that has recently been contested in 2002, 2008, 2014, and 2020. The next election will be in 2026. | Class 2Class 2 U.S. senators belong to the electoral cycle that has recently been contested in 2002, 2008, 2014, and 2020. The next election will be in 2026. | C | Class 3Class 3 U.S. senators belong to the electoral cycle that has recently been contested in 2004, 2010, 2016, and 2022. The next election will be in 2028. | Class 3Class 3 U.S. senators belong to the electoral cycle that has recently been contested in 2004, 2010, 2016, and 2022. The next election will be in 2028. | Class 3Class 3 U.S. senators belong to the electoral cycle that has recently been contested in 2004, 2010, 2016, and 2022. The next election will be in 2028. | Class 3Class 3 U.S. senators belong to the electoral cycle that has recently been contested in 2004, 2010, 2016, and 2022. The next election will be in 2028. | Class 3Class 3 U.S. senators belong to the electoral cycle that has recently been contested in 2004, 2010, 2016, and 2022. The next election will be in 2028. | Class 3Class 3 U.S. senators belong to the electoral cycle that has recently been contested in 2004, 2010, 2016, and 2022. The next election will be in 2028. |
| # | Senator | Party | Dates in office | Electoral history | T | C | T | Electoral history | Dates in office | Party | Senator | # |
| Vacant | Vacant | Vacant | Dec 28, 1846 – Dec 7, 1848 | Legislature failed to elect. | — | 29th | — | Legislature failed to elect. | Dec 28, 1846 – Dec 7, 1848 | Vacant | Vacant | Vacant |
| Vacant | Vacant | Vacant | Dec 28, 1846 – Dec 7, 1848 | Legislature failed to elect. | — | 30th | — | Legislature failed to elect. | Dec 28, 1846 – Dec 7, 1848 | Vacant | Vacant | Vacant |
| 1 | George W. Jones | Democratic | Dec 7, 1848 – Mar 3, 1859 | Elected in 1848. | 1 | 30th | 1 | Elected in 1848. | Dec 7, 1848 – Feb 22, 1855 | Democratic | Augustus C. Dodge | 1 |
| 1 | George W. Jones | Democratic | Dec 7, 1848 – Mar 3, 1859 | Elected in 1848. | 1 | 31st | 2 | Re-elected in 1849.Resigned to become U.S. Minister to Spain, having lost re-election. | Dec 7, 1848 – Feb 22, 1855 | Democratic | Augustus C. Dodge | 1 |
| 1 | George W. Jones | Democratic | Dec 7, 1848 – Mar 3, 1859 | Elected in 1848. | 1 | 32nd | 2 | Re-elected in 1849.Resigned to become U.S. Minister to Spain, having lost re-election. | Dec 7, 1848 – Feb 22, 1855 | Democratic | Augustus C. Dodge | 1 |
| 1 | George W. Jones | Democratic | Dec 7, 1848 – Mar 3, 1859 | Re-elected in 1852.Lost renomination. | 2 | 33rd | 2 | Re-elected in 1849.Resigned to become U.S. Minister to Spain, having lost re-election. | Dec 7, 1848 – Feb 22, 1855 | Democratic | Augustus C. Dodge | 1 |
| 1 | George W. Jones | Democratic | Dec 7, 1848 – Mar 3, 1859 | Re-elected in 1852.Lost renomination. | 2 | 33rd | 2 | | Feb 22, 1855 – Mar 3, 1855 | Vacant | Vacant | Vacant |
| 1 | George W. Jones | Democratic | Dec 7, 1848 – Mar 3, 1859 | Re-elected in 1852.Lost renomination. | 2 | 34th | 3 | Elected in 1855.Elected invalidated, as the Iowa Senate had not participated in it. | Mar 4, 1855 – Jan 5, 1857 | Free Soil | James Harlan | 2 |
| 1 | George W. Jones | Democratic | Dec 7, 1848 – Mar 3, 1859 | Re-elected in 1852.Lost renomination. | 2 | 34th | 3 | | Jan 5, 1857 – Jan 29, 1857 | Vacant | Vacant | | 2 |
| 1 | George W. Jones | Democratic | Dec 7, 1848 – Mar 3, 1859 | Re-elected in 1852.Lost renomination. | 2 | 34th | 3 | Re-elected to finish his vacant term. | Jan 29, 1857 – May 15, 1865 | Republican | James Harlan | 2 |
| 1 | George W. Jones | Democratic | Dec 7, 1848 – Mar 3, 1859 | Re-elected in 1852.Lost renomination. | 2 | 35th | 3 | Re-elected to finish his vacant term. | Jan 29, 1857 – May 15, 1865 | Republican | James Harlan | 2 |
| 2 | James W. Grimes | Republican | Mar 4, 1859 – Dec 6, 1869 | Elected in 1858. | 3 | 36th | 3 | Re-elected to finish his vacant term. | Jan 29, 1857 – May 15, 1865 | Republican | James Harlan | 2 |
| 2 | James W. Grimes | Republican | Mar 4, 1859 – Dec 6, 1869 | Elected in 1858. | 3 | 37th | 4 | Re-elected in 1860.Resigned to become U.S. Secretary of the Interior. | Jan 29, 1857 – May 15, 1865 | Republican | James Harlan | 2 |
| 2 | James W. Grimes | Republican | Mar 4, 1859 – Dec 6, 1869 | Elected in 1858. | 3 | 38th | 4 | Re-elected in 1860.Resigned to become U.S. Secretary of the Interior. | Jan 29, 1857 – May 15, 1865 | Republican | James Harlan | 2 |
| 2 | James W. Grimes | Republican | Mar 4, 1859 – Dec 6, 1869 | Re-elected in 1864.Resigned due to ill health. | 4 | 39th | 4 | Re-elected in 1860.Resigned to become U.S. Secretary of the Interior. | Jan 29, 1857 – May 15, 1865 | Republican | James Harlan | 2 |
| 2 | James W. Grimes | Republican | Mar 4, 1859 – Dec 6, 1869 | Re-elected in 1864.Resigned due to ill health. | 4 | 39th | 4 | | May 15, 1865 – Jan 13, 1866 | Vacant | Vacant | Vacant |
| 2 | James W. Grimes | Republican | Mar 4, 1859 – Dec 6, 1869 | Re-elected in 1864.Resigned due to ill health. | 4 | 39th | 4 | Elected to finish Harlan's term.Lost nomination for the next term. | Jan 13, 1866 – Mar 3, 1867 | Republican | Samuel J. Kirkwood | 3 |
| 2 | James W. Grimes | Republican | Mar 4, 1859 – Dec 6, 1869 | Re-elected in 1864.Resigned due to ill health. | 4 | 40th | 5 | Elected in 1866.Lost re-election. | Mar 4, 1867 – Mar 3, 1873 | Republican | James Harlan | 4 |
| 2 | James W. Grimes | Republican | Mar 4, 1859 – Dec 6, 1869 | Re-elected in 1864.Resigned due to ill health. | 4 | 41st | 5 | Elected in 1866.Lost re-election. | Mar 4, 1867 – Mar 3, 1873 | Republican | James Harlan | 4 |
| Vacant | Vacant | Vacant | Dec 6, 1869 – Jan 18, 1870 | | 4 | 41st | 5 | Elected in 1866.Lost re-election. | Mar 4, 1867 – Mar 3, 1873 | Republican | James Harlan | 4 |
| 3 | James B. Howell | Republican | Jan 18, 1870 – Mar 3, 1871 | Elected to finish Grimes's term.Retired. | 4 | 41st | 5 | Elected in 1866.Lost re-election. | Mar 4, 1867 – Mar 3, 1873 | Republican | James Harlan | 4 |
| 4 | George G. Wright | Republican | Mar 4, 1871 – Mar 3, 1877 | Elected in 1870.Retired. | 5 | 42nd | 5 | Elected in 1866.Lost re-election. | Mar 4, 1867 – Mar 3, 1873 | Republican | James Harlan | 4 |
| 4 | George G. Wright | Republican | Mar 4, 1871 – Mar 3, 1877 | Elected in 1870.Retired. | 5 | 43rd | 6 | Elected in 1872. | Mar 4, 1873 – Aug 4, 1908 | Republican | William B. Allison | 5 |
| 4 | George G. Wright | Republican | Mar 4, 1871 – Mar 3, 1877 | Elected in 1870.Retired. | 5 | 44th | 6 | Elected in 1872. | Mar 4, 1873 – Aug 4, 1908 | Republican | William B. Allison | 5 |
| 5 | Samuel J. Kirkwood | Republican | Mar 4, 1877 – Mar 7, 1881 | Elected in 1876 or 1877.Resigned to become U.S. Secretary of the Interior. | 6 | 45th | 6 | Elected in 1872. | Mar 4, 1873 – Aug 4, 1908 | Republican | William B. Allison | 5 |
| 5 | Samuel J. Kirkwood | Republican | Mar 4, 1877 – Mar 7, 1881 | Elected in 1876 or 1877.Resigned to become U.S. Secretary of the Interior. | 6 | 46th | 7 | Re-elected in 1878. | Mar 4, 1873 – Aug 4, 1908 | Republican | William B. Allison | 5 |
| 5 | Samuel J. Kirkwood | Republican | Mar 4, 1877 – Mar 7, 1881 | Elected in 1876 or 1877.Resigned to become U.S. Secretary of the Interior. | 6 | 47th | 7 | Re-elected in 1878. | Mar 4, 1873 – Aug 4, 1908 | Republican | William B. Allison | 5 |
| 6 | James W. McDill | Republican | Mar 8, 1881 – Mar 3, 1883 | Appointed to continue Kirkwood's term.Elected in 1882 to finish Kirkwood's term.Retired. | 6 | 47th | 7 | Re-elected in 1878. | Mar 4, 1873 – Aug 4, 1908 | Republican | William B. Allison | 5 |
| 7 | James F. Wilson | Republican | Mar 4, 1883 – Mar 3, 1895 | Elected in 1882. | 7 | 48th | 7 | Re-elected in 1878. | Mar 4, 1873 – Aug 4, 1908 | Republican | William B. Allison | 5 |
| 7 | James F. Wilson | Republican | Mar 4, 1883 – Mar 3, 1895 | Elected in 1882. | 7 | 49th | 8 | Re-elected in 1884. | Mar 4, 1873 – Aug 4, 1908 | Republican | William B. Allison | 5 |
| 7 | James F. Wilson | Republican | Mar 4, 1883 – Mar 3, 1895 | Elected in 1882. | 7 | 50th | 8 | Re-elected in 1884. | Mar 4, 1873 – Aug 4, 1908 | Republican | William B. Allison | 5 |
| 7 | James F. Wilson | Republican | Mar 4, 1883 – Mar 3, 1895 | Re-elected in 1888.Retired. | 8 | 51st | 8 | Re-elected in 1884. | Mar 4, 1873 – Aug 4, 1908 | Republican | William B. Allison | 5 |
| 7 | James F. Wilson | Republican | Mar 4, 1883 – Mar 3, 1895 | Re-elected in 1888.Retired. | 8 | 52nd | 9 | Re-elected in 1890. | Mar 4, 1873 – Aug 4, 1908 | Republican | William B. Allison | 5 |
| 7 | James F. Wilson | Republican | Mar 4, 1883 – Mar 3, 1895 | Re-elected in 1888.Retired. | 8 | 53rd | 9 | Re-elected in 1890. | Mar 4, 1873 – Aug 4, 1908 | Republican | William B. Allison | 5 |
| 8 | John H. Gear | Republican | Mar 4, 1895 – Jul 14, 1900 | Elected in 1894.Re-elected in 1900, but died. | 9 | 54th | 9 | Re-elected in 1890. | Mar 4, 1873 – Aug 4, 1908 | Republican | William B. Allison | 5 |
| 8 | John H. Gear | Republican | Mar 4, 1895 – Jul 14, 1900 | Elected in 1894.Re-elected in 1900, but died. | 9 | 55th | 10 | Re-elected in 1896. | Mar 4, 1873 – Aug 4, 1908 | Republican | William B. Allison | 5 |
| 8 | John H. Gear | Republican | Mar 4, 1895 – Jul 14, 1900 | Elected in 1894.Re-elected in 1900, but died. | 9 | 56th | 10 | Re-elected in 1896. | Mar 4, 1873 – Aug 4, 1908 | Republican | William B. Allison | 5 |
| Vacant | Vacant | Vacant | Jul 14, 1900 – Aug 22, 1900 | | 9 | 56th | 10 | Re-elected in 1896. | Mar 4, 1873 – Aug 4, 1908 | Republican | William B. Allison | 5 |
| 9 | Jonathan P. Dolliver | Republican | Aug 22, 1900 – Oct 15, 1910 | Appointed to finish Gear's term. | 9 | 56th | 10 | Re-elected in 1896. | Mar 4, 1873 – Aug 4, 1908 | Republican | William B. Allison | 5 |
| 9 | Jonathan P. Dolliver | Republican | Aug 22, 1900 – Oct 15, 1910 | Appointed to begin the vacant term.Elected in 1902 to finish the vacant term. | 10 | 57th | 10 | Re-elected in 1896. | Mar 4, 1873 – Aug 4, 1908 | Republican | William B. Allison | 5 |
| 9 | Jonathan P. Dolliver | Republican | Aug 22, 1900 – Oct 15, 1910 | Appointed to begin the vacant term.Elected in 1902 to finish the vacant term. | 10 | 58th | 11 | Re-elected in 1902.Renominated in 1908 but died before the general election. | Mar 4, 1873 – Aug 4, 1908 | Republican | William B. Allison | 5 |
| 9 | Jonathan P. Dolliver | Republican | Aug 22, 1900 – Oct 15, 1910 | Appointed to begin the vacant term.Elected in 1902 to finish the vacant term. | 10 | 59th | 11 | Re-elected in 1902.Renominated in 1908 but died before the general election. | Mar 4, 1873 – Aug 4, 1908 | Republican | William B. Allison | 5 |
| 9 | Jonathan P. Dolliver | Republican | Aug 22, 1900 – Oct 15, 1910 | Re-elected in 1907.Died. | 11 | 60th | 11 | Re-elected in 1902.Renominated in 1908 but died before the general election. | Mar 4, 1873 – Aug 4, 1908 | Republican | William B. Allison | 5 |
| 9 | Jonathan P. Dolliver | Republican | Aug 22, 1900 – Oct 15, 1910 | Re-elected in 1907.Died. | 11 | 60th | 11 | | Aug 4, 1908 – Nov 24, 1908 | Vacant | Vacant | Vacant |
| 9 | Jonathan P. Dolliver | Republican | Aug 22, 1900 – Oct 15, 1910 | Re-elected in 1907.Died. | 11 | 60th | 11 | Elected to finish Allison's term. | Nov 24, 1908 – Jul 30, 1926 | Republican | Albert B. Cummins | 6 |
| 9 | Jonathan P. Dolliver | Republican | Aug 22, 1900 – Oct 15, 1910 | Re-elected in 1907.Died. | 11 | 61st | 12 | Re-elected in 1909. | Nov 24, 1908 – Jul 30, 1926 | Republican | Albert B. Cummins | 6 |
| Vacant | Vacant | Vacant | Oct 15, 1910 – Nov 12, 1910 | | 11 | 61st | 12 | Re-elected in 1909. | Nov 24, 1908 – Jul 30, 1926 | Republican | Albert B. Cummins | 6 |
| 10 | Lafayette Young | Republican | Nov 12, 1910 – Apr 11, 1911 | Appointed to continue Dolliver's term.Lost election to finish Dolliver's term. | 11 | 61st | 12 | Re-elected in 1909. | Nov 24, 1908 – Jul 30, 1926 | Republican | Albert B. Cummins | 6 |
| 10 | Lafayette Young | Republican | Nov 12, 1910 – Apr 11, 1911 | Appointed to continue Dolliver's term.Lost election to finish Dolliver's term. | 11 | 62nd | 12 | Re-elected in 1909. | Nov 24, 1908 – Jul 30, 1926 | Republican | Albert B. Cummins | 6 |
| 11 | William S. Kenyon | Republican | Apr 12, 1911 – Feb 24, 1922 | Elected to finish Dolliver's term. | 11 | 62nd | 12 | Re-elected in 1909. | Nov 24, 1908 – Jul 30, 1926 | Republican | Albert B. Cummins | 6 |
| 11 | William S. Kenyon | Republican | Apr 12, 1911 – Feb 24, 1922 | Re-elected in 1913. | 12 | 63rd | 12 | Re-elected in 1909. | Nov 24, 1908 – Jul 30, 1926 | Republican | Albert B. Cummins | 6 |
| 11 | William S. Kenyon | Republican | Apr 12, 1911 – Feb 24, 1922 | Re-elected in 1913. | 12 | 64th | 13 | Re-elected in 1914. | Nov 24, 1908 – Jul 30, 1926 | Republican | Albert B. Cummins | 6 |
| 11 | William S. Kenyon | Republican | Apr 12, 1911 – Feb 24, 1922 | Re-elected in 1913. | 12 | 65th | 13 | Re-elected in 1914. | Nov 24, 1908 – Jul 30, 1926 | Republican | Albert B. Cummins | 6 |
| 11 | William S. Kenyon | Republican | Apr 12, 1911 – Feb 24, 1922 | Re-elected in 1918.Resigned to become Judge of the U.S. Court of Appeals. | 13 | 66th | 13 | Re-elected in 1914. | Nov 24, 1908 – Jul 30, 1926 | Republican | Albert B. Cummins | 6 |
| 11 | William S. Kenyon | Republican | Apr 12, 1911 – Feb 24, 1922 | Re-elected in 1918.Resigned to become Judge of the U.S. Court of Appeals. | 13 | 67th | 14 | Re-elected in 1920.Lost renomination, then died. | Nov 24, 1908 – Jul 30, 1926 | Republican | Albert B. Cummins | 6 |
| 12 | Charles A. Rawson | Republican | Feb 24, 1922 – Dec 1, 1922 | Appointed to continue Kenyon's term.Retired when his successor was elected. | 13 | 67th | 14 | Re-elected in 1920.Lost renomination, then died. | Nov 24, 1908 – Jul 30, 1926 | Republican | Albert B. Cummins | 6 |
| 13 | Smith W. Brookhart | Republican | Dec 1, 1922 – Apr 12, 1926 | Elected to finish Kenyon's term. | 13 | 67th | 14 | Re-elected in 1920.Lost renomination, then died. | Nov 24, 1908 – Jul 30, 1926 | Republican | Albert B. Cummins | 6 |
| 13 | Smith W. Brookhart | Republican | Dec 1, 1922 – Apr 12, 1926 | Elected to finish Kenyon's term. | 13 | 68th | 14 | Re-elected in 1920.Lost renomination, then died. | Nov 24, 1908 – Jul 30, 1926 | Republican | Albert B. Cummins | 6 |
| 13 | Smith W. Brookhart | Republican | Dec 1, 1922 – Apr 12, 1926 | Re-elected in 1924.Lost election challenge. | 14 | 69th | 14 | Re-elected in 1920.Lost renomination, then died. | Nov 24, 1908 – Jul 30, 1926 | Republican | Albert B. Cummins | 6 |
| 14 | Daniel F. Steck | Democratic | Apr 12, 1926 – Mar 3, 1931 | Successfully challenged his predecessor's election.Lost re-election. | 14 | 69th | 14 | Re-elected in 1920.Lost renomination, then died. | Nov 24, 1908 – Jul 30, 1926 | Republican | Albert B. Cummins | 6 |
| 14 | Daniel F. Steck | Democratic | Apr 12, 1926 – Mar 3, 1931 | Successfully challenged his predecessor's election.Lost re-election. | 14 | 69th | 14 | | Jul 30, 1926 – Aug 7, 1926 | Vacant | Vacant | Vacant |
| 14 | Daniel F. Steck | Democratic | Apr 12, 1926 – Mar 3, 1931 | Successfully challenged his predecessor's election.Lost re-election. | 14 | 69th | 14 | Appointed to continue Cummins's term.Elected in 1926 to finish Cummins's term.Retired. | Aug 7, 1926 – Mar 3, 1927 | Republican | David W. Stewart | 7 |
| 14 | Daniel F. Steck | Democratic | Apr 12, 1926 – Mar 3, 1931 | Successfully challenged his predecessor's election.Lost re-election. | 14 | 70th | 15 | Elected in 1926.Lost renomination and then lost re-election as an Independent. | Mar 4, 1927 – Mar 3, 1933 | Republican | Smith W. Brookhart | 8 |
| 14 | Daniel F. Steck | Democratic | Apr 12, 1926 – Mar 3, 1931 | Successfully challenged his predecessor's election.Lost re-election. | 14 | 71st | 15 | Elected in 1926.Lost renomination and then lost re-election as an Independent. | Mar 4, 1927 – Mar 3, 1933 | Republican | Smith W. Brookhart | 8 |
| 15 | L. J. Dickinson | Republican | Mar 4, 1931 – Jan 3, 1937 | Elected in 1930.Lost re-election. | 15 | 72nd | 15 | Elected in 1926.Lost renomination and then lost re-election as an Independent. | Mar 4, 1927 – Mar 3, 1933 | Republican | Smith W. Brookhart | 8 |
| 15 | L. J. Dickinson | Republican | Mar 4, 1931 – Jan 3, 1937 | Elected in 1930.Lost re-election. | 15 | 73rd | 16 | Elected in 1932.Died. | Mar 4, 1933 – Jul 16, 1936 | Democratic | Louis Murphy | 9 |
| 15 | L. J. Dickinson | Republican | Mar 4, 1931 – Jan 3, 1937 | Elected in 1930.Lost re-election. | 15 | 74th | 16 | Elected in 1932.Died. | Mar 4, 1933 – Jul 16, 1936 | Democratic | Louis Murphy | 9 |
| 15 | L. J. Dickinson | Republican | Mar 4, 1931 – Jan 3, 1937 | Elected in 1930.Lost re-election. | 15 | 74th | 16 | | Jul 16, 1936 – Nov 3, 1936 | Vacant | Vacant | Vacant |
| 15 | L. J. Dickinson | Republican | Mar 4, 1931 – Jan 3, 1937 | Elected in 1930.Lost re-election. | 15 | 74th | 16 | Elected to finish Murphy's term. | Nov 3, 1936 – Jan 3, 1945 | Democratic | Guy Gillette | 10 |
| 16 | Clyde L. Herring | Democratic | Jan 3, 1937 – Jan 3, 1943 | Elected in 1936. Did not take seat until Jan 15, 1937 in order to remain Governor of Iowa.Lost re-election. | 16 | 75th | 16 | Elected to finish Murphy's term. | Nov 3, 1936 – Jan 3, 1945 | Democratic | Guy Gillette | 10 |
| 16 | Clyde L. Herring | Democratic | Jan 3, 1937 – Jan 3, 1943 | Elected in 1936. Did not take seat until Jan 15, 1937 in order to remain Governor of Iowa.Lost re-election. | 16 | 76th | 17 | Re-elected in 1938.Lost re-election. | Nov 3, 1936 – Jan 3, 1945 | Democratic | Guy Gillette | 10 |
| 16 | Clyde L. Herring | Democratic | Jan 3, 1937 – Jan 3, 1943 | Elected in 1936. Did not take seat until Jan 15, 1937 in order to remain Governor of Iowa.Lost re-election. | 16 | 77th | 17 | Re-elected in 1938.Lost re-election. | Nov 3, 1936 – Jan 3, 1945 | Democratic | Guy Gillette | 10 |
| 17 | George A. Wilson | Republican | Jan 3, 1943 – Jan 3, 1949 | Elected in 1942. Did not take seat until Jan 14, 1943 in order to remain Governor of Iowa.Lost re-election. | 17 | 78th | 17 | Re-elected in 1938.Lost re-election. | Nov 3, 1936 – Jan 3, 1945 | Democratic | Guy Gillette | 10 |
| 17 | George A. Wilson | Republican | Jan 3, 1943 – Jan 3, 1949 | Elected in 1942. Did not take seat until Jan 14, 1943 in order to remain Governor of Iowa.Lost re-election. | 17 | 79th | 18 | Elected in 1944. | Jan 3, 1945 – Jan 3, 1969 | Republican | Bourke B. Hickenlooper | 11 |
| 17 | George A. Wilson | Republican | Jan 3, 1943 – Jan 3, 1949 | Elected in 1942. Did not take seat until Jan 14, 1943 in order to remain Governor of Iowa.Lost re-election. | 17 | 80th | 18 | Elected in 1944. | Jan 3, 1945 – Jan 3, 1969 | Republican | Bourke B. Hickenlooper | 11 |
| 18 | Guy Gillette | Democratic | Jan 3, 1949 – Jan 3, 1955 | Elected in 1948.Lost re-election. | 18 | 81st | 18 | Elected in 1944. | Jan 3, 1945 – Jan 3, 1969 | Republican | Bourke B. Hickenlooper | 11 |
| 18 | Guy Gillette | Democratic | Jan 3, 1949 – Jan 3, 1955 | Elected in 1948.Lost re-election. | 18 | 82nd | 19 | Re-elected in 1950. | Jan 3, 1945 – Jan 3, 1969 | Republican | Bourke B. Hickenlooper | 11 |
| 18 | Guy Gillette | Democratic | Jan 3, 1949 – Jan 3, 1955 | Elected in 1948.Lost re-election. | 18 | 83rd | 19 | Re-elected in 1950. | Jan 3, 1945 – Jan 3, 1969 | Republican | Bourke B. Hickenlooper | 11 |
| 19 | Thomas E. Martin | Republican | Jan 3, 1955 – Jan 3, 1961 | Elected in 1954.Retired. | 19 | 84th | 19 | Re-elected in 1950. | Jan 3, 1945 – Jan 3, 1969 | Republican | Bourke B. Hickenlooper | 11 |
| 19 | Thomas E. Martin | Republican | Jan 3, 1955 – Jan 3, 1961 | Elected in 1954.Retired. | 19 | 85th | 20 | Re-elected in 1956. | Jan 3, 1945 – Jan 3, 1969 | Republican | Bourke B. Hickenlooper | 11 |
| 19 | Thomas E. Martin | Republican | Jan 3, 1955 – Jan 3, 1961 | Elected in 1954.Retired. | 19 | 86th | 20 | Re-elected in 1956. | Jan 3, 1945 – Jan 3, 1969 | Republican | Bourke B. Hickenlooper | 11 |
| 20 | Jack Miller | Republican | Jan 3, 1961 – Jan 3, 1973 | Elected in 1960. | 20 | 87th | 20 | Re-elected in 1956. | Jan 3, 1945 – Jan 3, 1969 | Republican | Bourke B. Hickenlooper | 11 |
| 20 | Jack Miller | Republican | Jan 3, 1961 – Jan 3, 1973 | Elected in 1960. | 20 | 88th | 21 | Re-elected in 1962Retired. | Jan 3, 1945 – Jan 3, 1969 | Republican | Bourke B. Hickenlooper | 11 |
| 20 | Jack Miller | Republican | Jan 3, 1961 – Jan 3, 1973 | Elected in 1960. | 20 | 89th | 21 | Re-elected in 1962Retired. | Jan 3, 1945 – Jan 3, 1969 | Republican | Bourke B. Hickenlooper | 11 |
| 20 | Jack Miller | Republican | Jan 3, 1961 – Jan 3, 1973 | Re-elected in 1966.Lost re-election. | 21 | 90th | 21 | Re-elected in 1962Retired. | Jan 3, 1945 – Jan 3, 1969 | Republican | Bourke B. Hickenlooper | 11 |
| 20 | Jack Miller | Republican | Jan 3, 1961 – Jan 3, 1973 | Re-elected in 1966.Lost re-election. | 21 | 91st | 22 | Elected in 1968.Retired. | Jan 3, 1969 – Jan 3, 1975 | Democratic | Harold Hughes | 12 |
| 20 | Jack Miller | Republican | Jan 3, 1961 – Jan 3, 1973 | Re-elected in 1966.Lost re-election. | 21 | 92nd | 22 | Elected in 1968.Retired. | Jan 3, 1969 – Jan 3, 1975 | Democratic | Harold Hughes | 12 |
| 21 | Dick Clark | Democratic | Jan 3, 1973 – Jan 3, 1979 | Elected in 1972.Lost re-election. | 22 | 93rd | 22 | Elected in 1968.Retired. | Jan 3, 1969 – Jan 3, 1975 | Democratic | Harold Hughes | 12 |
| 21 | Dick Clark | Democratic | Jan 3, 1973 – Jan 3, 1979 | Elected in 1972.Lost re-election. | 22 | 94th | 23 | Elected in 1974.Lost re-election. | Jan 3, 1975 – Jan 3, 1981 | Democratic | John Culver | 13 |
| 21 | Dick Clark | Democratic | Jan 3, 1973 – Jan 3, 1979 | Elected in 1972.Lost re-election. | 22 | 95th | 23 | Elected in 1974.Lost re-election. | Jan 3, 1975 – Jan 3, 1981 | Democratic | John Culver | 13 |
| 22 | Roger Jepsen | Republican | Jan 3, 1979 – Jan 3, 1985 | Elected in 1978.Lost re-election. | 23 | 96th | 23 | Elected in 1974.Lost re-election. | Jan 3, 1975 – Jan 3, 1981 | Democratic | John Culver | 13 |
| 22 | Roger Jepsen | Republican | Jan 3, 1979 – Jan 3, 1985 | Elected in 1978.Lost re-election. | 23 | 97th | 24 | Elected in 1980. | Jan 3, 1981 – present | Republican | Chuck Grassley | 14 |
| 22 | Roger Jepsen | Republican | Jan 3, 1979 – Jan 3, 1985 | Elected in 1978.Lost re-election. | 23 | 98th | 24 | Elected in 1980. | Jan 3, 1981 – present | Republican | Chuck Grassley | 14 |
| 23 | Tom Harkin | Democratic | Jan 3, 1985 – Jan 3, 2015 | Elected in 1984. | 24 | 99th | 24 | Elected in 1980. | Jan 3, 1981 – present | Republican | Chuck Grassley | 14 |
| 23 | Tom Harkin | Democratic | Jan 3, 1985 – Jan 3, 2015 | Elected in 1984. | 24 | 100th | 25 | Re-elected in 1986. | Jan 3, 1981 – present | Republican | Chuck Grassley | 14 |
| 23 | Tom Harkin | Democratic | Jan 3, 1985 – Jan 3, 2015 | Elected in 1984. | 24 | 101st | 25 | Re-elected in 1986. | Jan 3, 1981 – present | Republican | Chuck Grassley | 14 |
| 23 | Tom Harkin | Democratic | Jan 3, 1985 – Jan 3, 2015 | Re-elected in 1990. | 25 | 102nd | 25 | Re-elected in 1986. | Jan 3, 1981 – present | Republican | Chuck Grassley | 14 |
| 23 | Tom Harkin | Democratic | Jan 3, 1985 – Jan 3, 2015 | Re-elected in 1990. | 25 | 103rd | 26 | Re-elected in 1992. | Jan 3, 1981 – present | Republican | Chuck Grassley | 14 |
| 23 | Tom Harkin | Democratic | Jan 3, 1985 – Jan 3, 2015 | Re-elected in 1990. | 25 | 104th | 26 | Re-elected in 1992. | Jan 3, 1981 – present | Republican | Chuck Grassley | 14 |
| 23 | Tom Harkin | Democratic | Jan 3, 1985 – Jan 3, 2015 | Re-elected in 1996. | 26 | 105th | 26 | Re-elected in 1992. | Jan 3, 1981 – present | Republican | Chuck Grassley | 14 |
| 23 | Tom Harkin | Democratic | Jan 3, 1985 – Jan 3, 2015 | Re-elected in 1996. | 26 | 106th | 27 | Re-elected in 1998. | Jan 3, 1981 – present | Republican | Chuck Grassley | 14 |
| 23 | Tom Harkin | Democratic | Jan 3, 1985 – Jan 3, 2015 | Re-elected in 1996. | 26 | 107th | 27 | Re-elected in 1998. | Jan 3, 1981 – present | Republican | Chuck Grassley | 14 |
| 23 | Tom Harkin | Democratic | Jan 3, 1985 – Jan 3, 2015 | Re-elected in 2002. | 27 | 108th | 27 | Re-elected in 1998. | Jan 3, 1981 – present | Republican | Chuck Grassley | 14 |
| 23 | Tom Harkin | Democratic | Jan 3, 1985 – Jan 3, 2015 | Re-elected in 2002. | 27 | 109th | 28 | Re-elected in 2004. | Jan 3, 1981 – present | Republican | Chuck Grassley | 14 |
| 23 | Tom Harkin | Democratic | Jan 3, 1985 – Jan 3, 2015 | Re-elected in 2002. | 27 | 110th | 28 | Re-elected in 2004. | Jan 3, 1981 – present | Republican | Chuck Grassley | 14 |
| 23 | Tom Harkin | Democratic | Jan 3, 1985 – Jan 3, 2015 | Re-elected in 2008Retired. | 28 | 111th | 28 | Re-elected in 2004. | Jan 3, 1981 – present | Republican | Chuck Grassley | 14 |
| 23 | Tom Harkin | Democratic | Jan 3, 1985 – Jan 3, 2015 | Re-elected in 2008Retired. | 28 | 112th | 29 | Re-elected in 2010. | Jan 3, 1981 – present | Republican | Chuck Grassley | 14 |
| 23 | Tom Harkin | Democratic | Jan 3, 1985 – Jan 3, 2015 | Re-elected in 2008Retired. | 28 | 113th | 29 | Re-elected in 2010. | Jan 3, 1981 – present | Republican | Chuck Grassley | 14 |
| 24 | Joni Ernst | Republican | Jan 3, 2015 – present | Elected in 2014. | 29 | 114th | 29 | Re-elected in 2010. | Jan 3, 1981 – present | Republican | Chuck Grassley | 14 |
| 24 | Joni Ernst | Republican | Jan 3, 2015 – present | Elected in 2014. | 29 | 115th | 30 | Re-elected in 2016. | Jan 3, 1981 – present | Republican | Chuck Grassley | 14 |
| 24 | Joni Ernst | Republican | Jan 3, 2015 – present | Elected in 2014. | 29 | 116th | 30 | Re-elected in 2016. | Jan 3, 1981 – present | Republican | Chuck Grassley | 14 |
| 24 | Joni Ernst | Republican | Jan 3, 2015 – present | Re-elected in 2020. | 30 | 117th | 30 | Re-elected in 2016. | Jan 3, 1981 – present | Republican | Chuck Grassley | 14 |
| 24 | Joni Ernst | Republican | Jan 3, 2015 – present | Re-elected in 2020. | 30 | 118th | 31 | Re-elected in 2022. | Jan 3, 1981 – present | Republican | Chuck Grassley | 14 |
| 24 | Joni Ernst | Republican | Jan 3, 2015 – present | Re-elected in 2020. | 30 | 119th | 31 | Re-elected in 2022. | Jan 3, 1981 – present | Republican | Chuck Grassley | 14 |
| To be determined in the 2026 election. | To be determined in the 2026 election. | To be determined in the 2026 election. | To be determined in the 2026 election. | To be determined in the 2026 election. | 31 | 120th | 31 | Re-elected in 2022. | Jan 3, 1981 – present | Republican | Chuck Grassley | 14 |
| To be determined in the 2026 election. | To be determined in the 2026 election. | To be determined in the 2026 election. | To be determined in the 2026 election. | To be determined in the 2026 election. | 31 | 121st | 32 | To be determined in the 2028 election. | To be determined in the 2028 election. | To be determined in the 2028 election. | To be determined in the 2028 election. | To be determined in the 2028 election. |
| # | Senator | Party | Years in office | Electoral history | T | C | T | Electoral history | Years in office | Party | Senator | # |
| Class 2 | Class 2 | Class 2 | Class 2 | Class 2 | Class 2 | C | Class 3 | Class 3 | Class 3 | Class 3 | Class 3 | Class 3 |